1) I definitely like the magnetic craze. I think it's a fun, interesting idea for polish and nail art.
2) Magnetic nail polish is persnickety. It's definitely not something that I found to be quick and easy. Depending on your magnet size, nail curve, nail length, strength of magnet etc., it can totally affect your look. Some nails I retried over four times to get the look I wanted. I still wasn't always satisfied.
3) I normally am a HUGE fan of China Glaze. It is my number one polish. Love. But as far as wearability and usability, I was not very happy with my results. The magnet was weak and I had lots of trouble with magnet application. My polish chipped really fast--some less than 24 hours (unlike my Layla Magneffects, which is some of the longest wearing polish I have ever owned). What I did like better than Layla was the closeness of the diagonal stripes of China Glaze's magnet.
Both colors were at least two coats (sometimes three depending on if the magnet worked to my liking) and had a top coat of Seche Vite.
Instant Chemistry with the star burst magnet:
Attraction with the diagonal stripes: